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Recurrent miscarriage is defined as two or more consecutive pregnancy losses before 20 weeks, and affects roughly 1 in 100 couples trying to conceive. Many women carry this grief alone, often blamed on stress, destiny, or a body that is somehow "not strong enough."
The Investigations You Should Ask For
According to the ESHRE 2023 guidelines, the most comprehensive international standard for recurrent pregnancy loss, investigations should be systematic and cover at least seven evidence-based domains:
1. Genetic testing: Chromosomal abnormalities are the single most common cause of early miscarriage, accounting for up to 50–60% of first-trimester losses. There are two important tests here:
- Karyotyping of both partners: A simple blood test that maps out your chromosomes. It checks for structural abnormalities, such as a balanced translocation, where a parent's chromosomes are rearranged in a way that doesn't affect them personally but can cause problems in the pregnancy.
- Products of conception (POC) testing/Chorionic villus testing: When a miscarriage occurs, sending the pregnancy tissue for genetic analysis (karyotype or array CGH) can tell you whether that specific pregnancy had a chromosomal defect.
2. Uterine (anatomical) investigations: The shape and structure of your uterus matter enormously for a pregnancy to implant and grow. Structural problems account for around 10–15% of recurrent losses.
- Transvaginal Ultrasound (TVS): It can identify fibroids, polyps, or a septate uterus (a wall of tissue dividing the uterine cavity).
- Saline Infusion Sonography (SIS) or Hysteroscopy: A more detailed look inside the uterine cavity. Hysteroscopy, where a thin camera is passed into the uterus, is the gold standard. It can detect and often treat problems like a uterine septum, adhesions, or polyps in the same procedure.
- 3D Ultrasound: This can easily delineate abnormalities in uterine shape without any procedure.
3. Hormonal testing: Hormonal imbalances can interfere with implantation and early pregnancy maintenance.
- Thyroid Function Tests (TSH, Free T4): Even a mildly underactive or overactive thyroid can cause recurrent losses. The target TSH in pregnancy is ideally below 2.5 mIU/L, stricter than the general population range. This is an affordable, widely available test.
- Prolactin levels: Elevated prolactin can disrupt ovulation and early pregnancy support.
- Fasting insulin and glucose / HOMA-IR (for PCOS screening): Polycystic Ovary Syndrome (PCOS) is extremely common in Indian women and is associated with an increased miscarriage risk, partly due to insulin resistance.
- Progesterone and Luteal Phase Assessment: Low progesterone in early pregnancy is controversial as a standalone cause, but your doctor may assess it in context.
4. Thrombophilia (blood clotting) investigations: Certain clotting conditions, inherited or acquired, can cause tiny blood clots in the placenta, cutting off the pregnancy's blood supply.
- Antiphospholipid Syndrome (APS) testing: This is arguably the most important blood test for recurrent miscarriage because APS is treatable. A positive result needs to be confirmed on a second test 12 weeks later to be considered clinically significant. Antiphospholipid antibodies are found in approximately 15% of women with recurrent miscarriage, compared to fewer than 2% in women with uncomplicated pregnancies. It involves testing for:
- Lupus anticoagulant
- Anticardiolipin antibodies (IgG and IgM)
- Anti-beta-2-glycoprotein-1 antibodies
- Inherited thrombophilia screen: This includes tests like Factor V Leiden mutation, Prothrombin gene mutation, Protein C, Protein S, and Antithrombin III. While these are tested routinely in many Western guidelines, in India, their clinical significance in recurrent miscarriage is still being refined.
5. Immunological investigations: The immune system plays a crucial role in pregnancy. Too aggressive an immune response can reject the embryo; too weak, and infections thrive.
- ANA (Antinuclear Antibody) and autoimmune screen: To rule out underlying autoimmune conditions like lupus (SLE) that can contribute to losses.
- Natural Killer (NK) cell testing: This is not part of routine guidelines yet, but some reproductive immunologists do investigate peripheral or uterine NK cell levels.
6. Male factor testing: Sperm DNA fragmentation testing is increasingly recognised as relevant. High levels of DNA damage in sperm are linked not just to difficulty conceiving, but to early pregnancy loss.
7. Lifestyle and environmental factors: This is the one domain that does not involve a blood test or a scan, but it is firmly part of the ESHRE 2023 guidelines for a reason. Certain lifestyle and environmental factors are directly linked to increased miscarriage risk, and most of them are modifiable.
- BMI: Both a very high and a very low BMI are independently associated with recurrent pregnancy loss. Undernutrition in women coexists alongside rising obesity rates, which is particularly relevant. Your doctor should assess your BMI and, if needed, refer you to a dietitian before your next conception attempt.
- Smoking: Smoking damages egg quality, impairs implantation, and increases miscarriage risk, and passive smoking matters too. Both partners should be asked about this.
- Alcohol: Even moderate alcohol consumption has been associated with increased miscarriage risk. Complete abstinence is advised when actively trying to conceive.
- Caffeine: High caffeine intake (above 200 mg per day, roughly two cups of coffee) has been linked to pregnancy loss in some studies.
- Stress and mental health: While stress alone is not a proven direct cause of miscarriage, chronic psychological stress affects hormonal balance, immune function, and overall health.
- Environmental and occupational exposures: Prolonged exposure to pesticides, heavy metals, solvents, or radiation has been flagged by research as a potential risk factor. If your work or living environment involves any of these, mention it to your doctor.
Recurrent miscarriages can be traumatic, which is why it is important to get the right kind of tests done. Speak to your doctor about them now.
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FAQs on Recurrent Miscarriage: What Investigations Should You Ask For
- How many miscarriages do I need to have before investigations are done?
Most guidelines recommend starting investigations after two consecutive miscarriages, especially if you are over 35. After three losses, a complete workup is considered standard of care. However, if a single loss occurred late (after 10 weeks) or involved a foetal heartbeat, investigation even after a single loss is reasonable. - Is recurrent miscarriage caused by stress or lifestyle factors?
Stress alone is not a proven direct cause of recurrent miscarriage, though it affects overall health. Factors like uncontrolled thyroid disease, PCOS, smoking, extreme BMI (very high or very low), and alcohol do contribute to risk and are modifiable. - If no cause is found, can I still have a successful pregnancy?
Yes, studies show that even when no cause is identified (which happens in roughly 50% of cases), 65–75% of couples go on to have a successful pregnancy with supportive care, close monitoring, and early pregnancy surveillance.